Welcome to the forum,
We all hope that you can find out all you need to know so that you can enjoy your car.

To determine if you have an air leak causing the problem, make sure the tank is at least 1/2 full, park the car on a hill facing down hill overnight. If it does not have the problem in the morning then probably you have an air leak into the fuel system.
Given he changed the filters, probably the leak is some where around the filters, my guess it the bolt holding the secondary filter on.

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Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving